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  1. #1
    Join Date
    Dec 2010
    Posts
    26

    chiller btu testing

    just wanted to know if this was a proper way to do a basic btu test? thanks
    Wes,

    I have attached the BTU test sheet for a 1-ton chiller. Please note the bottom right corner for a place to keep the temperature for each minute. The instructions for the test are as follows:

    1) You must have the exact volume of water contained within the chiller and system. It would be easiest to calculate this volume if you can tie the input and output lines together that run to the air handler. Or, you must empty the system and measure the amount of water exactly to the gallon that you add to fill the system completely.
    2) Allow the water to heat up and stabilize to around 90-95 degrees F either by allowing the pump to run without the compressor kicking on or cut the thermostat of the chiller up to 90-95 degrees to allow the water to get that hot and once it reaches 90-95 then set the chiller thermostat down to 45 degrees and when the compressor kicks on allow a few moments for the refrigerant to flow and the unit to begin working. When the temperature begins to drop start timing and start recording the temperature.
    3) Measure and record the temperature of the water each minute for 10-15 minutes. After the 10 or 15 minutes stop the refrigerated part of the chiller but leave the pump on and write the temperature down. Monitor the temperature and if it drops any further then use this as a final temperature.
    4) Take the total volume of water(in gallons) and multiply it by 8.34 to give you the total weight of water in lbs.
    5) Take the total weight of water in lbs. and multiply it by the total difference(starting temp vs final temp) in temperature measured on the water from step #3.
    6) Take the number you get from the calculation in step #5 and multiply it by 6(if you measured water temp for 10 mins) or by 4(if you measured the water temp for 15 mins) to give you the total BTUs.

  2. #2
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,609
    GPM times delta T divided by 24 = evaporator tons

    You're goin' around the world to get next door with that nutroll of calculations you're talkin' about........

  3. #3
    Join Date
    Dec 2010
    Posts
    26
    so basically the formula i have is in-correct? what is delta T?

  4. #4
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,609
    1 ton or 1000 tons, if you're working with a chiller and you don't know what delta T means, you're way behind the power curve. It's temperature differential between inlet and outlet water. For any more info than that, you'll have to put some history in your profile so we'll know who we're speaking with and what your level of experience is.

  5. #5
    Join Date
    Dec 2010
    Posts
    26
    i bought a 10 ton chiller and installed it myself. It doesnt seem to be working at any were near 10 tons using two separate williams air handlers for cooling. I have a hvac contractor servicing the unit, and i want him, or me, to do a btu test after i spent alot of $$. I'm mechanically inclined, but i only have general ac knowledge. The manufacturer is the one who gave me the btu test which i posted on this link. temperature differential can easily be done, sounds like the gpm flow will be the harder measurement.

  6. #6
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,006
    Quote Originally Posted by freeze22 View Post
    i bought a 10 ton chiller and installed it myself...
    Quote Originally Posted by freeze22 View Post
    ...He is recommending a plate heat exchanger. I'm just not sure if i want to spend a few thousand more into the unit for parts and labor, without a guarantee it will perform at the 120,000 btu of cooling or close too.
    who engineered this thing?

    i probably would recommend replacing the evaporator heat exchanger too (although this is on your comments of what may/may not be working well and you have provided 0 technical details of how the chiller is working). yet you want the contractor to guarantee something that they did not engineer, provide or install?

    i, too, am possibly recommending the evap be changed...do you want me to guarantee it too? and i have about as much responsibility for this thing as your contractor!


    Quote Originally Posted by freeze22 View Post
    ...The reason for the test and calling the private contractor, was because the unit wasn't keeping up with the demand of any were near what a 10 ton should perform...
    maybe the demand is greater than 10 tons. got water or glycol? temperatures in/out? gpm? lots going on here. and 10 tons of process work is much different that 10 tons of regular ol' air conditioning.


    i am not trying to bust your balls, but it is now time to give someone the keys to this car and let them drive it. you said that you are not a a chiller tech. you may have gotten away cheap on the install, but it does not seem cheap now...and it won't be cheap to fix either (i hope that it is something simple and cheap, but experience and your posts say otherwise). maybe you are right. maybe there is a design flaw or the compressor(s) may be faulty. without any numbers...you only can get speculation on the cause of your issues.
    It's tube brushing season...93% done (39.35 miles of tubing)...only 1,242 tubes to go!

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  7. #7
    Join Date
    Dec 2010
    Posts
    26
    guarantee is another misleading word. Chill king engineered everything, although, the welds on the frame that holds the chill tank, and the electrical controls looks like a inexperienced teenager designed this, so i use the term engineered loosely.The contractor is checking prices and it looks like close to 2,000 plus labor on the exchangers, so i have to decide if i want to sell the unit or fix it. the install was easy for me because i have a fabrication shop for off-road, so making manifolds, insulating lines inside that weren't done rite at Chill king as well as outside lines. I installed the air handlers, made custom stands, plumbed condensation lines, and did the duct work at 80 sq inches per ton with one 7.5 ton and one 3 ton williams/lanco air handlers, and mounted the condensers. the chiller in a heavy heat load couldn't chill the water below 51 degrees which pulled a minimal amount of heat out of the air i believe 10-12 without checking, this is with the 3 ton shut off. I will get more info from the contractor, he did check the water temp going in/out, also the gpm will be checked. I used a mixture of 75/25 glycol that i purchased from grainger made for use on water chillers. I'm in so-cal so the lowest emp we ever see is 40 f.
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  8. #8
    Join Date
    Jan 2009
    Location
    Not in Iran
    Posts
    992
    seems as if 40 * is good., what exactly are u trying to cool
    no signature blast'em man blast'em
    !!!KILL THE TERRORIST!!!

  9. #9
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,578
    Quote Originally Posted by mlkwal1 View Post
    seems as if 40 * is good., what exactly are u trying to cool
    I think he meant oat, 40*

  10. #10
    Join Date
    Dec 2010
    Posts
    26
    the lowest temperature outside is 40*F so 75/25 mix was recommended.I was just chilling a huge band room with heat from amps and people, as well as other office rooms. The chiller itself on the 7.5 ton air handler alone, under a heavy heat load, cannot get the water below 51* which in turn pulls a minimal amount of heat out of the air.

  11. #11
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,609
    "Chillers Use this forum to discuss all about chillers. Remember, no DIY."


    This is the heading at the top of the thread listing. Pay special attention to the last sentence. It's time to let your contractor do his job, or find someone that is familiar with what you need and get them to do it.

  12. #12
    Join Date
    Nov 2006
    Location
    US
    Posts
    112
    What is the Brand and Model # of your chiller

  13. #13
    Join Date
    Dec 2010
    Posts
    26
    it is a 10 chill king chiller. They are a mom and pop shop. I always try to let contractors do there jobs, and chill king gave me the formula to test the unit. The contractor said he had never heard of this method, but it was a simple test without a precise flow meter to test gpm so we did it. The unit only tested at 83,591 btu. I honestly think that is correct. The reason for the test and calling the private contractor, was because the unit wasn't keeping up with the demand of any were near what a 10 ton should perform. I am extremely disappointed in the unit, and the customer service from chill king in Texas.

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